A variety of problems related to gene action in virus development is proposed for investigation. Particular emphasis is placed on studies of the control of transcription and on the particular DNA-transcription enzyme interactions which determine, at least in part, the program of gene action in virus infection. The viruses to be studied are the bacteriophages T4 and SPO1 in their hosts, E. coli and B. subtilis. RNA polymerase from uninfected and infected cells will be isolated, characterized, resolved into components and sites of interaction with viral DNA will be studied. The mechanism of replication coupled transcription of the so-called "late" T4 genes will be further analyzed. A variety of in vivo studies of transcription during SPO1 virus development are also proposed with particular emphasis on gene-specific and general mechanisms for shutting off viral transcription in the infected cell. Investigations of the connection between replication and transcription in the cell cycle of Saccharomyces cerevisiae will be undertaken.